Imitation of intentional actions and internal state language in infancy predict preschool theory of mind skills

Abstract

The present study examined whether infants' imitation of intentional actions, concurrent vocabulary, and later internal state lexicon predicted their “theory of mind” (ToM) at preschool age. Initially, 14- and 18-month-olds completed an imitation task on intentional action understanding. Concurrent general vocabulary and internal state language at 32 months was also assessed. At approximately 4 years of age, children were retested with an interactive game measuring intention understanding, a false belief task or the Theory of Mind Scale (Wellman & Liu, 2004), and the PPVT. Infants' performance on the imitation task predicted their later concept of intention. Furthermore, internal state language was highly predictive of later ToM. These findings suggest that there is developmental continuity between precursors to ToM in infancy and ToM in the preschool years.

Acknowledgments

This research was supported by an operating grant awarded to the second author from the Social Sciences and Humanities Research Council of Canada. The first author was supported by a graduate fellowship from the Natural Sciences and Engineering Research Council of Canada (NSERC). This research was submitted by Kara M. Olineck in partial fulfillment of the requirements for the doctoral degree in psychology at Concordia University. Portions of this work were presented in June 2006 at the XVth Biennial International Conference on Infant Studies, Kyoto, Japan.

The authors wish to thank Lauren Gilbert, Sandra Misrachi, and Sara Quirke for help with collecting and coding the data.